Hadronic decay of exotic mesons consisting of four charm quarks

In 2020, a di-<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi></a:math> resonance centered at around 6.9 GeV was discovered by the LHCb Collaboration and was later confirmed by the ATLAS and CMS Collaborations. In addition to the 6.9-GeV resonance, its low-energy counterpart centered at around 6552 MeV was also observed by the CMS Collaboration. They are generally considered as fully charm tetraquarks. In this paper, we calculate the inclusive decay width of molecules composed of two <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>J</c:mi><c:mo>/</c:mo><c:mi>ψ</c:mi></c:math>’s and genuine fully charm tetraquarks into light hadrons and into open charms, respectively. Assuming them as <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>S</e:mi></e:math>-wave states, we consider all possible spin configurations, namely, spin-0 and spin-2, that decay exclusively into double <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>J</g:mi><g:mo>/</g:mo><g:mi>ψ</g:mi></g:math>, and find that the ratio (<i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi mathvariant="script">R</i:mi></i:math>) of the decay width for the light-hadron final states to that for the charmed final states differs significantly among different spin configurations, which can help to explore the nature of the observed di-<l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:mi>J</l:mi><l:mo>/</l:mo><l:mi>ψ</l:mi></l:math> resonances. Published by the American Physical Society 2024